Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
  • B01J20/103—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate comprising silica
  • B01J20/106—Perlite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D37/00—Processes of filtration
  • B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
  • B01J20/28004—Sorbent size or size distribution, e.g. particle size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/28023—Fibres or filaments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
  • B01J20/3202—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the carrier, support or substrate used for impregnation or coating
  • B01J20/3204—Inorganic carriers, supports or substrates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
  • B01J20/3202—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the carrier, support or substrate used for impregnation or coating
  • B01J20/3206—Organic carriers, supports or substrates
  • B01J20/3208—Polymeric carriers, supports or substrates
  • B01J20/321—Polymeric carriers, supports or substrates consisting of a polymer obtained by reactions involving only carbon to carbon unsaturated bonds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
  • B01J20/3202—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the carrier, support or substrate used for impregnation or coating
  • B01J20/3206—Organic carriers, supports or substrates
  • B01J20/3208—Polymeric carriers, supports or substrates
  • B01J20/3212—Polymeric carriers, supports or substrates consisting of a polymer obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
  • B01J20/3214—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the method for obtaining this coating or impregnating
  • B01J20/3217—Resulting in a chemical bond between the coating or impregnating layer and the carrier, support or substrate, e.g. a covalent bond
  • B01J20/3221—Resulting in a chemical bond between the coating or impregnating layer and the carrier, support or substrate, e.g. a covalent bond the chemical bond being an ionic interaction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
  • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
  • B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
  • B01J20/3242—Layers with a functional group, e.g. an affinity material, a ligand, a reactant or a complexing group
  • B01J20/3268—Macromolecular compounds
  • B01J20/327—Polymers obtained by reactions involving only carbon to carbon unsaturated bonds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J47/00—Ion-exchange processes in general; Apparatus therefor
  • B01J47/12—Ion-exchange processes in general; Apparatus therefor characterised by the use of ion-exchange material in the form of ribbons, filaments, fibres or sheets, e.g. membranes
  • B01J47/133—Precoat filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange

Definitions

• This invention is concerned with filter aid materials which, according to the invention, are coated with anion exchange resin of average particle diamter 0.05 to 1 micrometer, the resin being electrostatically bound to the surface of the filter aid material.
• Filter aids are well-known and are usually solid materials, insoluble in the liquid to be filtered, which are added to the liquid or are coated upon a filter or filter support, their purpose being to speed filtration, reduce fouling of the filter surface, reduce cracking of the filter layer, or otherwise to improve filtration characteristics.
• Materials which are frequently used as filter aids include cellulose fibers, diatomaceous earth, charcoal, expanded perlite and asbestos fibers.
• Filter aids are often treated to improve their effect upon the filter. They have been treated with soluble polyelectrolytes to change their surface characteristics, as described in U.S. Patent 4,190,532. They also have been modified chemically to give them ion exchange properties, as described in British Patent 1,123,908, or mixed with ground ion exchange resins having particle sizes of about 40 to 250 micrometers, and the resulting mixture used as a filter aid, as described in U.S. Patent 4190532, U.S.Patent 4,187,120 and British Patent 1,455,692.
• Filters are often prepared from flocculated mixtures of cation and anion exchange resins, either ground, conventional resins as taught in U.S. Patents 3,250,702 and 3,250,703, or from emulsion polymer ion exchange resins, as taught in U.S. Patent 4,200,695. These flocs may be coated on filter supports to be used for removal of colloidal and dissolved solids from water and other aqueous process streams. A major problem of filters using these filter media is a tendency for the filter layer to crack during use, which leads to particulate leakage and fouling of the filter support. Fibrous filter-aid material deposited on top of the filter layer significantly aids in the prevention of such cracks, thereby protecting the filter support and prolonging the useful life of the filter layer.
• cationic particles bearing anion exchange functional groups and having an average particle diameter of 0.05 to 1 micrometer, coated upon the surface of conventional filter aid materials, produces a cation-particle-coated filter aid material which is superior for many applications.
• Such cationic particles bind themselves electrostatically to the negatively charged surface which forms on filter aid materials when they are wet with water.
• the electrostatic bond thus formed is sufficiently strong to resist resin-particle separation from the surface of the filter aid material during rinsing or other treatment, this strong bonding being in marked contrast to the behavior of larger charged particles in contact with filter aid materials, as described in the above references.
• the particles, once bound may even be substantially irremovable from the filter aid surface.
• the materials of the present invention may be regarded as cation-particle-coated filter aids since they bear a surface coating of the fine cationic particles described above bound tightly to the filter aid by the electrostatic charges.
• the particles themselves may be regarded alternatively and interchangeably as cationic particles and as anion exchange resins, because they possess not only a cationic charge, but anion exchange functional groups in or on their insoluble polymer structure.
• cation-particle-coated filter aids possess a high surface area of active anion-exchange sites, for wherever the small cationic particles of anion resins are not in contact with the filter aid they are available for both adsorption and anion exchange.
• cation-particle-coated filter aid materials permit a significant increase in the total filtration capacity of a filter having an anion and cation exchange resin floc as a precoat and as an overcoat a layer of cation-particle-coated filter aid. There may be further overcoating of the filter with conventional filter aids.
• Suitable flocs are disclosed in published European Patent Specification 9394 (Application 793 019 36.5) and in U.S. Patents 3250 702 and 3250 703.
• the filter aids useful in preparing the compositions of the invention are well-known to those familiar with the filtration art. They include, but are not limited to, cellulose fibers, including those cellulose fibers which have been variously treated with commercial surface treatments, asbestos fibers, polyacrylonotrile fibers, charcoal, diatomaceous earth and expanded perlite.
• the cation particles used in this invention are those particles bearing anion exchange functional groups and having the very fine average particle diameter 0.05 to 1 micrometer, more preferably 0.05 to 0.2 micrometers. Smaller particle sizes encourage tighter bonding between the anion exchange resin particles and the surface of the filter aid materials. Strongly basic resins in this particle size range are preferred, and more preferred are those resins functionalised with quaternary amine functional groups.
• the improved filter aid compositions of the invention may be prepared by mixing a dispersion of the resin particles in water with a slurry of the filter aid material in water. As these materials are mixed, the positively charged resin particles bind electrostatically to the negatively charged surface of the filter aid material until the surface is saturated. This saturation typically occurs when about 2% or less of the resin, based on the dry weight of the filter aid material, has bound itself to the filter aid surface. Until the surface has been saturated, the supernatant liquid in the mixture is clear; at saturation the excess resin particles remain free, and the supernatant liquid is cloudy. Once the materials have been combined, the cation-particle-coated filter aid may be rinsed to remove excess unbound resin, with no loss of the bound resin from the surface of the filter aid.
• the filter aid compositions of the invention may be used for purposes similar to those of untreated filter aids; such uses being well known in the art.
• Conventional flow rates and levels of application may be used as guides for determining the optimum conditions for a particular application.
• This example illustrates the preparation of an improved, cation-particle-coated filter aid according to the present invention, from a commercial cellulose fiber filter aid material.
• a 8.79 g sample of cellulose fiber filter aid (marketed commercially by The Brown Co., 650 Main St., Berlin, NH. 03570 as Solka-Floc SW-40) was slurried in 300 ml of water.
• aqueous suspension of quaternary amine-functionalized, strongly basic, emulsion anion exchange resin having an average particle diameter of 0.1 micrometer was added. The mixture was shaken for one minute, and produced a clear supernatant liquid upon settling. The pH of this supernatant liquid, measured on a pH meter, was 9.6.
• the amount of emulsion anion exchange resin in the sample was 0.5%, based on the solid weight of filter aid and resin.
• This example illustrates the preparation of an improved cation-particle-coated filter aid according to the present invention from a commercial, treated filter aid material.
• a 94.8 g sample of 33.8% solids, cellulose fiber filter aid (marketed commercially by Ecodyne Corp. as "Ecocote") was slurried in 800 ml of water. The pH of this slurry was 6.0.
• a 2.0 ml portion of the emulsion anion exchange resin suspension described in Example 1 was added to the slurry and the mixture was shaken for 2 minutes. An additional 1.0 ml portion of the anion exchange resin was added, and the mixture was shaken for an additional 2 minutes.
• This example illustrates the preparation of a cation-particle-coated filter aid material according to the present invention which contains more anion exchange resin than that of Example 2.
• a 36.6 g sample of the cellulose fiber filter aid described in Example 2 was slurried in 300 ml of water, and 2.0 ml of the emulsion anion exchange resin suspension described in Example 1 was added; the mixture was shaken for 1 minute. Upon settling, the supernatant liquid was clear and the pH of the liquid was 8.3. This sample contained 1.4% anion exchange resins, based on the dry weight of filter aid material and resins.
• This example describes the preparation of a conventional cellulose fiber filter aid material treated with an amount of sodium hydroxide approximately equivalent to the hydroxyl functionality of the resin bound to the filter aid material in Example 1.
• the amount of hydroxyl functionality, but not the ion exchange capacity nor the presence of the finely divided cation particles of the cation-particle-coated filter aid materials is thus simulated.
• An 8.5 g sample of the cellulose fiber filter aid material used in Example 1 was slurried in 300 ml of deionized water. The pH of the supernatant water was measured as 6.7. A 2.0 ml portion of 0.1 N sodium hydroxide solution was added, and the mixture was shaken; the pH of the resulting, supernatant liquid was 9.3.
• This example illustrates the preparation of a conventional cellulose fiber filter aid material treated with a soluble, quaternary-amine-functionalized polymer, the resulting filter-aid material corresponding to materials of the prior art.
• a 8.5 g sample of the cellulose fiber filter aid material used in Example 1 was slurried in 300 ml. of water, and the pH of the supernatant liquid was determined to be 7.0.
• Catfloc ® was converted to the hydroxide form by treating it with a conventional, strongly basic anion exchange resin.
• a 0.15 g sample of a 1.83%-solids, aqueous solution of the polymer was added to the filter aid material and the mixture was shaken.
• the supernatant liquid had a measured pH of 9.3.
• This example illustrates the use of the filter aids of the present invention as overcoats to aid in filtration with flocculated, finely divided ion exchange resins, and compares the filtration effectiveness of conventionally overcoated filters with those employing the filter aids of the present invention.
• a floc was prepared from strongly basic and strongly acidic emulsion ion exchange resins according to U.S. Patent No. 4,200,695; this floc was precoated, at a level of 0.037 g/cm 2 of filter area (0.075 lbs/ft 2 ), or a total of 18.6 g of floc on a dry basis, onto a polypropylene, spiral-wound filter support with an average pore size of 20 ⁇ m at the service flow rate of 0.015 liters/min./cm 2 (3.7 gpm/ft2) ; the inlet pressure was maintained at approximately 34 kilo-Pascals (5 psig).
• the filter aid material was coated onto the deposited floc at a level of 0.016 g/cm 2 (0.033 lb/ft2), or 8.18 g of dry filter aid material, at the same flow rate.
• a suspension of approximately 1000 parts per billion hematite (Fe 2 0 3 ) having a particle size of 0.87 ⁇ m was prepared in water deionized to a conductivity of 10 x 10 6 ohm-cm, and this suspension was filtered through the filters prepared as described above at the 0.015 liters/min/cm 2 flow rate, but at a pressure of 170 kPa (25 psig).
• the pressure drop across the filters was monitored during the run, and the hematite leakage was monitored by passing 250-ml samples of the filtrate through 0.45- ⁇ m filters (Millipore Corp.); at the appearance of a slight yellow color on the filters, corresponding to about 10% leakage as measured by atomic absorption spectrometry, the run was terminated.
• the hematite removal by the filters being tested was determined by atomic absorption spectrometry, and is recorded as total grams of hematite removed.
• Table I summarizes the results of the above test with both the improved filter aids of the present invention and conventional filter aids.
• the filter support was precoated with 0.073 g/cm 2 of a floc prepared by mixing 12.39 g of ground, strongly basic resin with 24.79 g of ground, strongly acidic resin in 250 ml of deionized water and "smoothing" the resulting floc by the addition of 12 ml of 0.1% polyacrylic acid solutions.
• the ground resins are marketed commercially by Ecodyne Corp., Graver Water Division, under the respective designations Powdex® OH and Powdex® H; these ground resins have a median particle diameter of about 20 ⁇ m and a very broad particle size distribution.
• the polyacrylic acid solution is marketed commercially by Rohm and Haas Company, under the designation Acrysol® ASE-108.
• the materials of the present invention i.e., the cation-particle-coated filter aids of Examples 1, 2 and 3, possess significantly longer service lives and higher filtration capacities than the conventional filter aids of Examples 4 and 5 and the untreated filter aids.
• the comparison of untreated overcoat material with the cation-particle-coated filter aid material of the present invention clearly shows the superiority of a smaller amount of cation-particle-coated filter aid over a larger amount of conventional material. Note that, because the filter precoat in this comparison was different from that of the preceding runs, the results of this comparison should not be compared directly with those of the preceding runs.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Analytical Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Environmental & Geological Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Water Supply & Treatment (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Treatment Of Water By Ion Exchange (AREA)
• Filtering Materials (AREA)
• Filtration Of Liquid (AREA)
• Detergent Compositions (AREA)
• Lubricants (AREA)
• Paints Or Removers (AREA)

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Citations (9)

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• 1981
  • 1981-09-03 US US06/298,866 patent/US4594158A/en not_active Expired - Fee Related
• 1982
  • 1982-08-26 AT AT82304501T patent/ATE18139T1/de not_active IP Right Cessation
  • 1982-08-26 EP EP82304501A patent/EP0074221B1/de not_active Expired
  • 1982-08-26 DE DE8282304501T patent/DE3269397D1/de not_active Expired
  • 1982-08-27 AU AU87803/82A patent/AU558151B2/en not_active Ceased
  • 1982-08-31 ZA ZA826353A patent/ZA826353B/xx unknown
  • 1982-08-31 BR BR8205115A patent/BR8205115A/pt unknown
  • 1982-08-31 CA CA000410529A patent/CA1178748A/en not_active Expired
  • 1982-09-02 JP JP57151809A patent/JPS5845739A/ja active Granted
  • 1982-09-03 KR KR8203983A patent/KR890004800B1/ko active

Patent Citations (9)

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